@lucinternet: Military helicopters flying through a sandstorm can create the spectacular Kopp-Etchells Effect, a phenomenon where the rotor blades appear to emit sparks or a glowing halo. This occurs due to sand and dust particles impacting the titanium edges of the blades at high speeds, causing a process called triboluminescence—light produced by friction. The harsh environment intensifies the effect, as the blades encounter constant abrasion from sand grains. Named after two fallen soldiers, this effect is a stark visual reminder of the dangers and beauty of operating helicopters in extreme conditions, blending science and the raw intensity of military operations.