Dissecting a lightning strike, from flash to boom
It shot me down (Alessandro Rustighi/)Most lightning just bounces around within its cloud of origin. But the rogue charges that escape are enough to dazzle observers, inspire awe and fear (which is fair—the zaps do kill a few dozen people in the US every year), and make some magnificent thunder. A typical cloud-to-ground strike lasts for just a fraction of a second. Here’s how the short but brilliant lifetime of a bolt goes down.Electrons Bounce The show starts in a thunderhead, where ice particles collide so fast, they knock off each other’s electrons. That leaves positive charges hanging near the top of the cloud, while negative ones accumulate in the middle.Discharge EmergesEnergy zipping between opposing charges forms bolts. Given enough buildup, electricity escapes the cloud in a series of cascading branches roughly 160 feet long; a new spur forms every 50-millionths of a second.Paths ConnectAs negative charges shoot down from...