赖世雄中级美国英语Lesson71

 
　　71. Earth in Danger
　　Seeing is believing. But seeing a huge rock half the size of Earth smash into Jupiter in July 1996 was incredible. Can you imagine what would happen if Earth collided with a huge space rock？ It would be disastrous. In fact， it is thought that a meteor killed the dinosaurs millions of years ago.
　　A rock like the one that hit Jupiter could split Earth in two. Doing nothing about it is like waiting for the end of the world. So scientists plan to start project to identify all space rocks that could hit Earth.