So, I've been talking to a lot of NASA JPL scientists -- at JPL they are famous for the Mars rovers -- and the scientists, geologists always tell me that the real interesting science, the science-rich sites, are always at the cliffs.
我曾和许多NASA喷气推进实验室的科学家们聊过， 在喷气推进实验室，最出名的就是火星车。 科学家们和地质学家们经常告诉我， 真正有趣的科学、 富含科学知识的地点就是在悬崖峭壁上。