無(wú)標(biāo)題文檔
科學(xué)家觀察到宇宙爆炸
2005-2-23 環(huán)球教育論壇
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. Theresearchers say if the blast had occurred closer to Earth, it might have lead to the death of much of the planet's life.
天文學(xué)家探測(cè)到宇宙中有史以來(lái)最為明亮的一次爆炸。爆炸的亮光在銀河系一掃而過(guò)，光線如此明亮，以至于光從月球折射回來(lái)，把地球大氣層的外層都照亮了。研究人員說(shuō)，假如爆炸距離地球更近的話，可能會(huì)造成我們這個(gè)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.
這次巨大的宇宙爆炸是在去年12月底，由美國(guó)和歐洲的衛(wèi)星以及世界各地的射電望遠(yuǎn)鏡觀察到的。不容錯(cuò)過(guò)，就在一瞬間，亮度比滿盤明月都要亮，但是這種光線是高能度的伽瑪射線，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.
大衛(wèi)?帕爾默是美國(guó)洛斯阿拉莫斯國(guó)家實(shí)驗(yàn)室的天體物理學(xué)家，他表示這次爆炸總的能量相當(dāng)于10萬(wàn)年的太陽(yáng)光的能量。他說(shuō)：“換言之，這次在十分之一秒里釋放出的巨大能量，一千倍于整個(gè)銀河系所有星星能量的總合?！?
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.
觀測(cè)到這次爆炸亮光的科學(xué)家說(shuō)，亮光來(lái)自于人馬星座的一個(gè)孤立的中子星。有大約5萬(wàn)光年之遠(yuǎn)，這段距離光也要走上5萬(wàn)年。來(lái)自操控哈伯太空望遠(yuǎn)鏡機(jī)構(gòu)的天文學(xué)家安德魯??？藸栒f(shuō)，中子星是巨星解體后塌陷到只有20公里直徑大小的旋轉(zhuǎn)殘骸。
"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.
他說(shuō)：“巨星活的快，死的早，留下的是旋轉(zhuǎn)殘骸。我們所看到的是它們死后的樣子。比我們的想像要更有意思?！?br>
he 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.
導(dǎo)致發(fā)生宇宙大爆炸的中子星是一種的奇特類型叫做磁星，之所以這樣命名是因?yàn)樗袠O強(qiáng)的磁場(chǎng)，比一個(gè)普通中子星的一千倍還強(qiáng)或者是地球的一千萬(wàn)億倍。它的磁性可以在離月球一半的距離之外，把信用卡上的磁性掃光。在銀河系數(shù)十億顆恒星中只有十多個(gè)磁星被人們發(fā)現(xiàn)。
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.
天文學(xué)家認(rèn)為，這種星球的磁場(chǎng)導(dǎo)致了爆炸的發(fā)生，但是，他們不明白是如何發(fā)生的。一種可能的原因是這種爆炸很像有超級(jí)能量的太陽(yáng)耀斑。這就是磁星的磁場(chǎng)改變了形狀然后向本身內(nèi)部撞擊。因此磁場(chǎng)產(chǎn)生了電流，這樣的碰撞可以導(dǎo)致強(qiáng)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.
一種理論是星球表面的地震導(dǎo)致了能源的突然釋放。
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.
不論是什么原因，猛烈的放射線象肥皂沫一樣以四分之一光速向外噴出。這個(gè)能量很快顯示到地球的外大氣層，將在電離層中的原子擊開(kāi)，使它們發(fā)出比普通太陽(yáng)耀斑使它們發(fā)的更亮的光。它的能量是如此巨大，使無(wú)論是否指著自己方向的15個(gè)航天器上的儀器偏離角度。這種射線也穿過(guò)了一個(gè)美國(guó)X光波望遠(yuǎn)鏡。
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員布萊恩?詹茲勒表示如果這次爆炸發(fā)生在離我們太陽(yáng)系很近的距離，比如10光年遠(yuǎn)的話，它就會(huì)嚴(yán)重破壞我們的大氣層，很有可能導(dǎo)致生命物種的大量滅亡。
"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."
“這些物體同常不會(huì)在這么快的時(shí)間里變得這么大。我們習(xí)慣了在地下種下一棵橡樹(shù)種子，等上50年看它慢慢長(zhǎng)成一棵大橡樹(shù)。而這次我們就象站在種子面前，眼看只用了幾個(gè)星期的時(shí)間，種子就變成了大樹(shù)。這是非常不一般的，恐怕我們這輩子不會(huì)看到這種現(xiàn)像再發(fā)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.
這次事件的巨大能量甚至可以認(rèn)為是長(zhǎng)期存在的天文學(xué)之迷的一種離奇解釋?？茖W(xué)家們想知道伽馬射線短暫爆發(fā)這種奇特現(xiàn)象的起源，在最近的幾十年里他們觀測(cè)到了幾百次這種現(xiàn)象。他們表示這些短暫的閃亮和12月的中子星釋放伽瑪射線的道理是一樣的。 這些恒星可以解釋以前發(fā)生的一些現(xiàn)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.
為了解開(kāi)這個(gè)迷團(tuán)，美國(guó)太空總署在去年11月發(fā)射了以"雨燕"命名并配備有到現(xiàn)在為止設(shè)計(jì)的最敏感的伽馬射線探測(cè)器的航天器。美國(guó)洛斯阿拉莫斯國(guó)家實(shí)驗(yàn)室的大衛(wèi)?帕爾默說(shuō)，很幸運(yùn)"雨燕"僅僅在投入使用后一個(gè)月就觀測(cè)到了這一現(xiàn)象。他說(shuō)："有時(shí)走運(yùn)才是最佳策略"。
