1957年10月,苏联发射了一颗小金属球绕着地球飞行。自此以后,人类进入了太空时代。有人对太空探索嗤之以鼻,认为这种劳民伤财的活动置地球上的问题于不顾。其实,太空时代正以许多看得见和看不见的方式改变着我们的生活。燃料电池在 In October 1957, the Soviet Union launched a small metal ball flying around the earth. Since then, mankind has entered space age. Some people scoff at space exploration and think that such a laborious and unprofitable activity disregards the problems on the earth. In fact, the space age is changing our lives in many visible and invisible ways. Fuel cell at