A Phenomenon Overlooked
Many believe that the second lightning or 'repeating lightning' is just an optical illusion or light reflection on clouds or surfaces. However, a recent study by atmospheric physicists from the University of Colorado and the German Institute for Atmospheric Physics (IFU) proves otherwise: the sound of thunder itself can trigger additional lightning — a process called *acoustic-triggered re-ignition*.How Does Thunder 'Reignite' the Sky?
Thunder's shock waves — supersonic explosions caused by the sudden heating of air around the lightning channel — can create local pressure changes in the illuminated clouds. When these waves pass through zones with high ion concentration and almost critical electric fields, they cause micro-instabilities sufficient to restart the electrical spark. This process usually occurs between 0.3 to 1.8 seconds after the first lightning, explaining the sequence of lightning without any real location change.Empirical Evidence and Unique Records
Using a network of high-resolution acoustic sensors and ultra-fast cameras (100,000 frames per second), the research team successfully captured 27 cases of *acoustic-triggered lightning* in tropical lightning data over three years. One record showed three consecutive lightning strikes with exact temporal distances of 0.54, 0.61, and 0.69 seconds — aligning with the speed of sound wave propagation through cloud layers at specific temperatures and humidity levels.Implications for Safety and Weather Modeling
This discovery is not just an atmospheric wonder; it also affects how lightning warning systems are designed. Modern weather models now begin to include acoustic parameters as an additional risk factor in predicting cloud electrostatic activity. For communities in areas with frequent thunderstorms, it also emphasizes that the belief that 'the danger has passed' after the first lightning strike is a myth — the risk of electrical discharges still exists for more than one second after the thunder is heard.