[1] When the end of the world comes, we'll know what to blame. Scientists have found compelling evidence that the Sun has a baby brother, a dark star whose eccentric orbit is responsible for periodically showering the Earth with comets and meteorites.
[2] The dark star--named Nemesis by astronomers--is thought to be a brown dwarf" that spins round the Sun in an orbit so large it is measured in light years, the distance light travels in a year, equivalent to about 6,000 billion miles.
[3] The research suggests that, every 26m years, the star's eccentric orbit brings it within one light year of the solar system. There it causes havoc in the Oort Cloud, a huge region surrounding the solar system that contains billions of bits of cosmic rubble left over from the formation of planets.
[4] Of the millions of rocks it throws out of orbit at each visit, some hurtle Earthwards--and have several times nearly wiped out life on Earth.
[5] Astronomers have long wondered if the Sun has a smaller partner. Recently, two independent groups of researchers have found evidence of one.
[6] One group, led by John Matese, professor of physics at the University of Louisiana at Lafayette, confirms the notion that it is most likely to be a brown dwarf, a star that never accumulated enough mass to ignite and which has simply sat in space smouldering for billions of years.
[7] Matese studied 82 comets from the Oort Cloud and found common elements in the shape of their orbits that could only be explained if they had been influenced by the gravitational pull of an object several times the size of Jupiter and existing about 25,000 times farther from the Sun than the Earth.
[8] Matese said: "A companion to the Sun orbiting at these distances would have little effect on the planets. But it would play a big role in the way comets ' made their way' from their birth places in the planetary disc out to the Oort Cloud and on now they can return to the inner solar system."
[9] Further research was published by Richard Muller, professor of physics at the University of California, Berkeley, following analyses of moon rock samples brought back to Earth by Apollo 14.
[10] The absence of a protective atmosphere means the moon has been subjected to intense bombardment in its 4.5 billion-year existence.
[1]當世界末日來臨時我們將知道該去責備什麽。科學家們已發現明顯的跡象表明：太陽有壹個小弟弟，它是壹顆暗星，其偏心軌道導致彗星群和流星雨周期性降落地球。
[2]這顆被天文學家叫做復仇女神星的暗星被認為是壹顆“褐矮星”，它圍繞太陽旋轉的軌道大得要用光年計量，光年是光在壹年中走過的距離，大約等於 6萬億英裏。
[3]研究表明，每經過2600萬年，這顆星的偏心軌道就將它帶到距太陽系1光年的範圍內。在那裏，它引起了奧爾特雲的浩劫，奧爾特雲是壹個巨大的圍繞太陽系的區域，裏面包含了數十億從行星形成中分離出來的宇宙碎塊。
[4]它每壹次訪問太陽系時，都從軌道上甩出上百萬個巖塊，其中壹些飛向地球的方向——有幾次幾乎摧毀地球上的生命。
[5]天文學家長期以來壹直懷疑太陽是否有壹個小伴星。最近，兩個獨立的研究小組已經發現了壹些端倪。
[6]壹個由拉斐特的路易斯安娜大學物理學教授約翰·馬泰塞領導的小組證實了壹個想法，那就是它最有可能是壹顆褐矮星，這是壹種永遠也不能積聚足夠的質量著火燃燒的星，它只是在太空中數十億年地無焰悶燒。
[7]馬泰塞研究了奧爾特雲的82顆彗星，發現在它們軌道的形狀上有***同的因素，那只有在它們是被壹個數倍大於木星的天體的引力作用所影響，且這個天體距太陽的距離比地球要遠25，0000倍的情況下才能解釋。
[8]馬泰塞說：“壹個離太陽如此遙遠的伴星對行星的影響是微乎其微的。但是，在彗星從它們在行星盤的誕生地'前進'到奧爾特雲的方式上，以及它們能返回太陽系內部的途徑上，這顆星扮演著重要的角色。”
[9]加州大學伯克利分校的物理學教授理查德·馬勒在分析了“阿波羅14號”帶回的月球巖石標本之後，公布了進壹步的研究成果。
[10]由於缺乏大氣的保護，月球在它存在的45億年間遭受了強烈的撞擊。