Researchers at Beihang University in Beijing have unveiled a tiny and ultra-lightweight drone that can fly continuously as long as it receives sunlight. The CoulombFly, weighing about 4.2 grams—less than a piece of paper—features an electrostatic motor powered by natural light. Named after Coulomb’s Law, which describes the force created when similar or opposite particles at rest repel or attract each other, this drone addresses traditional challenges faced by tiny solar-powered drones.