Lightning strikes from a storm approaching Trieste, Italy. (Image credit: Jure Batagelj / 500px via Getty Images) The energy needed for thunderstorms could come from an avalanche of electrons seeded by extraterrestrial cosmic rays, a new study claims.Scientists already knew that lightning is an electrical discharge between thunderclouds and Earth's surface, but exactly how storm clouds obtain an electric field powerful enough to hurl a bolt has remained a mystery for centuries.Now, a new study h...