On August 1, 2025, researchers at Penn State University solved a centuries-old mystery dating back to Benjamin Franklin’s iconic kite experiment. Using advanced simulations and high-energy physics modeling, they uncovered the actual mechanism that initiates lightning in storm clouds.

Their findings show that intense electric fields within thunderclouds can accelerate free electrons to near-light speeds. These electrons then collide with atmospheric molecules, triggering a cascade of interactions—including the emission of X-rays—that ultimately give rise to a lightning bolt. This chain reaction also explains the elusive phenomenon of “dark lightning” (terrestrial gamma-ray flashes), observed by satellites but previously misunderstood.

The research marks a breakthrough not just in atmospheric science, but also in aviation safety and extreme weather forecasting.