VOA双语新闻 Scientists Observe Brightest Cosmic Explosion（在线收听）

Astronomers have detected the brightest explosion ever witnessed in the heavens. It was a flash of light from across our galaxy so powerful that it bounced off the Moon and illuminated Earth's upper atmosphere. The researchers say if the blast had occurred closer to Earth, it might have lead to the death of much of the planet's life.

天文学家探测到宇宙中有史以来最为明亮的一次爆炸。爆炸的亮光在银河系一扫而过，光线如此明亮，以至于光从月球折射回来，把地球大气层的外层都照亮了。研究人员说，假如爆炸距离地球更近的话，可能会造成我们这个星球上一半多的生物死亡。

The monstrous cosmic explosion took place late in December, observed by U.S. and European satellites and ground telescopes around the world. It was impossible to miss. It was brighter than a full moon for a fraction of a second, although it shone more brilliantly in high energy gamma rays than in the lower energy visible light.

这次巨大的宇宙爆炸是在去年12月底，由美国和欧洲的卫星以及世界各地的射电望远镜观察到的。不容错过，就在一瞬间，亮度比满盘明月都要亮，但是这种光线是高能度的伽玛射线，肉眼是看不到的。

Astrophysicist David Palmer of the U.S. government's Los Alamos National Laboratory says the amount of energy equaled 100,000 years worth of sunlight. "In other words, this was as much energy during that tenth of a second as all the other stars in the galaxy at that time, times over 1,000," he said.

大卫·帕尔默是美国洛斯阿拉莫斯国家实验室的天体物理学家，他表示这次爆炸总的能量相当于10万年的太阳光的能量。他说：“换言之，这次在十分之一秒里释放出的巨大能量，一千倍于整个银河系所有星星能量的总合。”

The scientists who observed the flash say it came from an isolated neutron star in the constellation Sagittarius about 50,000 light years away, the distance it takes light to travel in 50,000 years. Astronomer Andrew Fruchter of the institute that operates the Hubble Space Telescope describes a neutron star as the spinning remnant of a massive star that has collapsed into a diameter of only 20 kilometers.

观测到这次爆炸亮光的科学家说，亮光来自于人马星座的一个孤立的中子星。有大约5万光年之远，这段距离光也要走上5万年。来自操控哈伯太空望远镜机构的天文学家安德鲁·福克尔说，中子星是巨星解体后塌陷到只有20公里直径大小的旋转残骸。

"Massive stars live fast, die young, and leave spinning corpses. What we've seen is that their afterlives are even more interesting than we had thought," he said.

他说：“巨星活的快，死的早，留下的是旋转残骸。我们所看到的是它们死后的样子。比我们的想像要更有意思。”

The neutron star that caused the giant cosmic blast is an exotic type called a magnetar. It is so named because it has an extremely powerful magnetic field, 1,000 times stronger than an ordinary neutron star and a 1,000-trillion times that of Earth's. It is capable of erasing the magnetic information on a credit card at a distance halfway to the Moon. Only about a dozen magnetars are known among the billions of stars in the Milky Way.

导致发生宇宙大爆炸的中子星是一种的奇特类型叫做磁星，之所以这样命名是因为它有极强的磁场，比一个普通中子星的一千倍还强或者是地球的一千万亿倍。它的磁性可以在离月球一半的距离之外，把信用卡上的磁性扫光。在银河系数十亿颗恒星中只有十多个磁星被人们发现。

Astronomers believe the star's magnetic field caused the outburst, but do not understand how. One possibility is that the blast was like an ultra-powerful solar flare. This is where a magnetic field changes shape and bumps into itself. Since magnetic fields cause electrical currents, such a collision could have caused a monumental short circuit visible from Earth.

天文学家认为，这种星球的磁场导致了爆炸的发生，但是，他们不明白是如何发生的。一种可能的原因是这种爆炸很像有超级能量的太阳耀斑。这就是磁星的磁场改变了形状然后向本身内部撞击。因此磁场产生了电流，这样的碰撞可以导致强烈的短路并且可在地球上看到。

Or a quake on the star's surface might have caused the massive eruption of energy.

一种理论是星球表面的地震导致了能源的突然释放。

Whatever the cause, the blitz of radiation expanded outward in a bubble at about one-fourth the speed of light. This energy soon showered Earth's upper atmosphere, tearing apart atoms in a region called the ionosphere to a greater depth than an ordinary solar flare and causing them to glow. It was so powerful that it pushed the instruments of 15 spacecraft off scale, whether or not they were pointing in its direction. It also saturated a U.S. telescope watching in x-ray wavelengths.

不论是什么原因，猛烈的放射线象肥皂沫一样以四分之一光速向外喷出。这个能量很快显示到地球的外大气层，将在电离层中的原子击开，使它们发出比普通太阳耀斑使它们发的更亮的光。它的能量是如此巨大，使无论是否指着自己方向的15个航天器上的仪器偏离角度。这种射线也穿过了一个美国X光波望远镜。

Researcher Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics says if the explosion had occurred much closer to our solar system, say just 10 light years away, it would have severely damaged the atmosphere and possibly triggered a mass extinction of living things.

哈佛史密森天文物理中心的研究员布莱恩·詹兹勒表示如果这次爆炸发生在离我们太阳系很近的距离，比如10光年远的话，它就会严重破坏我们的大气层，很有可能导致生命物种的大量灭亡。

"These objects do not normally get this big this quickly. We're used to planting an acorn in the ground and maybe waiting 50 years for it to turn slowly into an oak tree. This time, it was like we were standing in front of the acorn and it popped up into a full tree just in the space of a few weeks," he said. "This was so extreme that this may not happen again in our lifetimes."

“这些物体同常不会在这么快的时间里变得这么大。我们习惯了在地下种下一棵橡树种子，等上50年看它慢慢长成一棵大橡树。而这次我们就象站在种子面前，眼看只用了几个星期的时间，种子就变成了大树。这是非常不一般的，恐怕我们这辈子不会看到这种现像再发生了。”

The tremendous power of the event suggests a novel solution to a long-standing astronomical mystery. Scientists want to know the origins of the strange phenomenon of brief gamma ray bursts observed hundreds of times over recent decades. They say these short-duration flashes emit gamma rays in the same way the neutron star did in December and that such stars could explain a large number of the occurrences.

这次事件的巨大能量甚至可以认为是长期存在的天文学之迷的一种离奇解释。科学家们想知道伽马射线短暂爆发这种奇特现象的起源，在最近的几十年里他们观测到了几百次这种现象。他们表示这些短暂的闪亮和12月的中子星释放伽玛射线的道理是一样的。 这些恒星可以解释以前发生的一些现象。

To get at this puzzle, the U.S. space agency launched a spacecraft named "Swift" last November with the most sensitive gamma ray detectors ever designed. David Palmer at the Los Alamos National Laboratory notes that, luckily, Swift saw this event after only one month on the job. "Sometimes being lucky is the best strategy," he said.

为了解开这个迷团，美国太空总署在去年11月发射了以"雨燕"命名并配备有到现在为止设计的最敏感的伽马射线探测器的航天器。美国洛斯阿拉莫斯国家实验室的大卫·帕尔默说，很幸运"雨燕"仅仅在投入使用后一个月就观测到了这一现象。他说："有时走运才是最佳策略"。