英语短文：小兄弟威胁着地球 2

[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.

[6]一个由拉斐特的路易斯安娜大学物理学教授约翰·马泰塞领导的小组证实了一个想法，那就是它最有可能是一颗褐矮星，这是一种永远也不能积聚足够的质量着火燃烧的星，它只是在太空中数十亿年地无焰闷烧。

[7]马泰塞研究了来自奥尔特云的82颗彗星，发现在它们轨道的形状上有共同的因素，那只有在它们是被一个数倍大于木星的天体的引力作用所影响，且这个天体距太阳的距离比地球要远25，0000倍的情况下才能解释。

[8]马泰塞说：“一个离太阳如此遥远的伴星对行星的影响是微乎其微的。但是，在彗星从它们在行星盘的诞生地'前进'到奥尔特云的方式上，以及它们能返回太阳系内部的途径上，这颗星扮演着重要的角色。”

[9]加州大学伯克利分校的
物理学教授理查德·马勒在分析了“阿波罗14号”带回的月球岩石标本之后，公布了进一步的研究成果。

[10]由于缺乏大气的保护，月球在它存在的45亿年间遭受了强烈的撞击。