报应女神」让恐龙灭绝！NASA努力寻找凶手！ http://www.nownews.com/2010/03/15/91-2580015.htm 国际中心／综合报导 是谁让恐龙灭种？美国太空总署(NASA)的科学家指出，一颗被喻为「死亡之星」(Death Star)、围绕太阳运行的矮星「报应女神」可能是凶手。六千五百万年前地球上恐龙灭绝 (呃…看到这个就不自觉地笑了起来…死星是星际大战里的太空要塞) 的主因，科学家相信跟地球不时受彗星撞击威胁有关，NASA从今年一月开始，就开始利用 太空望远镜扫描太空，希望找出这颗神秘星体。 科学家指出，这颗被称为「报应女神」(Nemesis)的矮星，距离地球约三分之一光年，亦 即地球和太阳之间距离的二万五千倍，体积约为木星的五倍，但实际位置不明。科学家相 信太阳系被一层巨大的冰体云团奥尔特云（Oort Cloud）包围，而「报应女神」的引力会 (国内译为欧特云…奥尔特云对岸的译法) 令奥尔特云中的巨型冰块如彗星般撞向行星。 (这位中文记者不知道彗星的昵称「脏雪球」…云特云是彗星的产地) 有古生物学家指地球约每隔二千六百万年便会遭受浩劫，相信彗星撞击便是引致这些灾难 的原因。 又，该则中文新闻应该译自以下这篇英文新闻 http://ppt.cc/CFam Invisible star 'shooting comets at Earth' By Paul Sutherland at The Sun From: NewsCore March 12, 2010 The dinosaurs may have died because an invisible brown dwarf star is throwing snowballs at us / AFP Source: AFP Brown dwarf could have caused mass extinctions Star is invisible and a long way away But heat-seeking telescope may find it AN invisible star responsible for the extinction of dinosaurs may be circling the Sun and causing comets to bombard the Earth, scientists said. The brown dwarf - up to five times the size of Jupiter - could be to blame for mass extinctions that occur here every 26 million years, The Sun reports. The star - nicknamed Nemesis by NASA scientists - would be invisible as it only emits infrared light and is incredibly distant. Nemesis is believed to orbit our solar system at 25,000 times the distance of the Earth to the Sun. As it spins through the galaxy, its gravitational pull drags icy bodies out of the Oort Cloud - a vast sphere of rock and dust twice as far away as Nemesis. These "snowballs" are thrown towards Earth as comets, causing devastation similar to the asteroid that wiped out the dinosaurs 65 million years ago. Now NASA scientists believe they will be able to find Nemesis using a new heat-seeking telescope that began scanning the skies in January. The Wide-Field Infrared Survey Explorer - expected to find a thousand brown dwarf stars within 25 light years of the Sun - has already sent back a photo of a comet possibly dislodged from the Oort Cloud. Scientists' first clue to the existence of Nemesis was the bizarre orbit of a dwarf planet called Sedna. Scientists believe its unusual, 12,000-year-long oval orbit could be explained by a massive celestial body. Mike Brown, who discovered Sedna in 2003, said: "Sedna is a very odd object - it shouldn't be there. "The only way to get on an eccentric orbit is to have some giant body kick you - so what is out there?" Professor John Matese, of the University of Louisiana at Lafayette, said most comets come from the same part of the Oort Cloud. He added: "There is statistically significant evidence that this concentration of comets could be caused by a companion to the Sun." --

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