When you change a current in a wire or move a magnet, the information about that change propagates through space at the speed of light. This is a direct consequence of Maxwell’s equations, where time-varying electric and magnetic fields generate each other and travel outward as electromagnetic waves. Mathematically, the propagation speed emerges from the coupling of permittivity and permeability of free space: c = 1 / sqrt(mu_0 * epsilon_0) This means the electromagnetic field itself updates causally, with no influence traveling faster than c. There is no instantaneous “action at a distance.” Even static-looking fields are really the result of past boundary conditions encoded in spacetime. But here’s the key distinction: A field transmitting information is not the same as matter responding to it. Once the field reaches a charged or magnetic object, the force is applied locally. At that point, classical dynamics takes over. According to Newton’s second law: F = ma So even if the fo...