[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.
 
    [1]當世界末日來臨時我們將知道該去責備什么�？茖W家們已發(fā)現明顯的跡象表明：太陽有一個小弟弟，它是一顆暗星，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一顆"褐矮星"，它圍繞太陽旋轉的軌道大得要用光年計量，光年是光在一年中走過的距離，大約等于 6萬億英里。

    [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光年的范圍內。在那里，它引起了奧爾特云的浩劫，奧爾特云是一個巨大的圍繞太陽系的區(qū)域，里面包含了數十億從行星形成中分離出來的宇宙碎塊。

    [4]它每一次訪問太陽系時，都從軌道上甩出上百萬個巖塊，其中一些飛向地球的方向--有幾次幾乎摧毀地球上的生命。

    [5]天文學家長期以來一直懷疑太陽是否有一個小伴星。最近，兩個獨立的研究小組已經發(fā)現了一些端倪。