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教学参考

操控光速的现代女“魔术师”

作者：vip  人气： 1070 次  时间：2004年11月16日  星级：

使光速降为零，过去认为是不可能的，但这个难题却使莉娜·豪蜚声全球。她已经成功地使光速减慢，直至使光完全停止，最后又使光重新启动。这一意义重大的新成果即使物理学界欣喜若狂，又使计算机生产者兴奋异常。

　　根据爱因斯坦的相对论，世界上最快物质运动速度是光速，光线每秒旅行29.9790万公里，从地球到太阳1.5亿公里的距离，光走行不到8分钟。1999年，科学家过行了一次革命性试验，首先使光速减慢，几乎达到与城市公路上行驶的汽车一样的速度（时速60公里），2001年，他们甚至让光直接停了下来。这看起来似乎不可能，但它的确是真实的。请不要忘记，光的传播速度不是一成不变的，而是在不同的介质中有着不同的速度。光的最快速度只有在真空和物质稀薄的空间才能达到，便如在空气中。随着穿过的介质浓密度增加，光速就减慢，光速在水中比在真空中减慢约30%。从科学的观点讲，这样的减慢是意义重大的，但是在普通的光学材料中减慢光速的程度存在一定限制，一般只会减慢到原来的几分之一。与人类在常规实验中涉及到的速度相比，普通介质中的光速还是太高了。慢化光速的实验者是41岁的丹麦女科学家、美国哈佛大学物理学教授莉娜·豪（LeneHau），她也是马萨诸塞州剑桥罗兰德科学院一个研究小组的负责人。

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