Everybody knows about lightning. Lightning is those dramatic white forks across the sky during thunderstorms. It’s what makes the thunder boom. It also strikes tall trees and people in exposed places. Lightning strikes kill between 75 and 150 people every year, and injures as many as 5,000.
We know a lot about what lightning does. But we know very little about what causes lightning in the first place. Lightning is electricity, like the electricity that powers our refrigerators and iPads. But it’s very different. Natural lightning jumps from one place to another, or arcs, much easier than less powerful electric arcs. We don’t know why. And we know hardly anything about why lightning happens at all.