在美国田纳西州东部坎伯兰山区有一个小镇,名叫橡树岭。橡树岭位于一条长16公里、宽3.2公里的橡树山谷里。橡树岭并不小,可是在世界地图乃至美国大大小小的地图上都看不到这个小镇,也很少有人知道这个地方。小镇甚至连名字都没有,如果不是多年以后曝光的一张照片,小镇仿佛不存在一样,而这一切的原因就是因为小镇是美国研究原子能的秘密基地。在第二次世界大战的时候,德国一直试图抢先研制核武器,而著名的科学家爱因斯坦知道这一情况后,马上联合一批科学家向当时的美国总统罗斯福写信建 There is a small town in the Cumberland Mountains of eastern Tennessee, named Oak Ridge. Oak Ridge is located in a 16 km long, 3.2 km wide oak valley. Oak Ridge is not small, but the town can not be seen on world maps and even on large and small U.S. maps, and few people know about it. The town does not even have a name. If it is not a photograph that has been exposed for many years, the town does not seem to exist. The reason for all this is that the town is a secret base for the United States to study atomic energy. At the time of World War II, Germany had been trying to pioneer the development of nuclear weapons. After the well-known scientist Einstein learned of this situation, he immediately joined a group of scientists to write letter to the then U.S. President Roosevelt