末日倒数 地球大撤退

　　If we faced a countdown to destruction, could we build a spacecraft to take us to new and habitable worlds? Can we Evacuate Earth? NGC's two-hour special examines this terrifying but scientifically plausible scenario by exploring how we could unite to ensure the survival of the human race有个科幻故事的宇航员，在太空中迷失方向时总能安全返回，不是因为他的导航技术，而是因为他总能记住剧本中的坐标。