The way you would put it to a nine-year-old is to say, "If a meteorite was coming to hit the Earth, how would you figure out if it was going to or not?"
عندما تقولها لذوي التسعة اعوام يكون السؤال، "اذا كان كويكب ليضرب الارض، كيف نعرف اذا كان سيصيب ام لا؟"