The discovery that the universe's expansion is accelerating came from observations of far-off supernovae in the 1990s, and was deemed worthy of the latest Nobel prize in physics.

20世纪90年代对于遥远的超新星的观测，发现了宇宙正在加速膨胀，被公认为使得2011年度诺贝尔物理学奖物有所值。

It has left theorists scratching their heads as to what causes it. The leading candidate is a "dark energy" that emanates from the quantum vacuum, and somehow manages to trump the steadying force of gravity. Other suggestions are that the effect is an illusion born of where we are sitting in the cosmos - or simply that gravity itself is weakened on large cosmic scales.

它却使得有的理论物理学家摸不着头脑，是什么原因造成宇宙加速膨胀的。主流的候选者是"暗能量"，源自量子真空，用某种方法胜过了把万物拉在一起的起稳定作用的引力。另外的建议则是，这个效果就类似于过去的我们就处在宇宙中心的地心说的错觉——或者简单的在宇宙学的大尺度上，引力的作用被削弱。

This last explanation has a big hurdle to overcome. Our current theory of gravity, Einstein's general theory of relativity, says that the force works in the same way everywhere. Its predictions have been confirmed on scales up to that of the solar system, which is as far as we have roamed to test it.

后一个解释有一个很大的障碍需要克服。我们目前的引力理论，爱因斯坦的广义相对论说，引力在宇宙各处有同样的行为。它的预言已经得到太阳系尺度上的验证，至少我们星际探测器的漫游就证实了这一点。

Galileons provide a neat workaround. They are the quantum particles associated with a field that is hypothesised to weaken gravity. Like the related "chameleon" particles, their influence is screened by the presence of matter. In a region of relatively high density, such as our solar system, their weakening effect is imperceptible, kicking in only over vast, emptier swathes of the cosmos - thus explaining the supernova observations.

伽利略子提供一个简洁的解决方法。它们是与一个假设的能够削弱引力的场相联系的粒子。像相关的"变色龙"粒子一样，它们的作用被物质所屏蔽。在相对高密度的区域，如我们的太阳系，他们的削弱作用是不能被观测的，只有在巨大而空虚的大片的宇宙中才有效——从而解释了超新星的观测。

It's a nice idea, but is it true? The answer depends on finding testable effects that we might use to prove the existence of the particles, says theorist Mark Trodden of the University of Pennsylvania in Philadelphia. "We are trying very hard to work out what they might be."

这是一个不错的主意，但它是对的吗？问题的答案取决于找到能够测试的效果，让我们能够证实它的存在，费城宾夕法尼亚大学的理论物理学家Mark Trodden说。"我们非常努力的研究它们可能是什么。"

• worthy [´wə:ði]   a.有价值的；值得的   (初中英语单词)
• candidate [´kændideit]   n.候选人；投考者   (初中英语单词)
• explanation [,eksplə´neiʃən]   n.解释；说明；辩解   (初中英语单词)
• overcome [,əuvə´kʌm]   vt.战胜，克服   (初中英语单词)
• system [´sistəm]   n.系统，体系，制度   (初中英语单词)
• existence [ig´zistəns]   n.存在；生存；生活   (初中英语单词)
• expansion [ik´spænʃən]   n.扩大；膨胀；发展   (高中英语单词)
• gravity [´græviti]   n.严肃；严重；重力   (高中英语单词)
• illusion [i´lu:ʒən]   n.幻觉；幻影；错觉   (高中英语单词)
• weaken [´wi:kən]   v.(使)弱化；衰弱；稀薄   (高中英语单词)
• related [ri´leitid]   a.叙述的；有联系的   (高中英语单词)
• relatively [´relətivli]   ad.比较地；相对地   (高中英语单词)
• finding [´faindiŋ]   n.发现物；判断；结果   (高中英语单词)
• far-off [´fɑ:rɔ:f]   a.远方的，遥远的   (英语四级单词)
• trying [´traiiŋ]   a.难堪的；费劲的   (英语四级单词)
• vacuum [´vækjuəm]   n.真空；空间   (英语六级单词)
• density [´densiti]   n.浓(稠)密；密度   (英语六级单词)