pretty cool sight. >> for one group of people it prompts them to ask what is behind those bolts. with that, lightning chasers were born. here's david muir. >> reporter: we've seen lightning captured on videotape. >> crazy. >> reporter: striking so fast that until now scientists have known remarkably little about how lightning actually works. new technology is allowing them to capture thousands of images every second. and watch what they can do slowing one lightning strike down, discovering that one bolt is often several distinct flashes. and when tall structures are involved, say a radio tower, lightning strike can actually originate from the structure and shoot upward. not the other way around. airplanes can also trigger lightning strikes. this animation shows the plane drawing lightning from above and below. look at the real thing. this one caught on tape. and then there's that age-old question. how much time do you have to take cover? >> if you can count the time