So-called light/EM wave/photon/radiation is nothing but alternating current within atoms/medium.

Light must coexisting with matter/medium. There is no light traveling in space. Light induces light over any distance instantly.

Based on Coulomb's law, F=Ke x e x e/R^2. Two electrons are connected by repulsion force at any distance, therefore they can share electrostatic force/EMF/energy/information instantly. Such repulsion force is called levity by scientists in the past, but they never discover its mechanism.

Atoms are constantly oscillating with the thermal energy they carry. That energy can radiate to any line of sight atoms through levity. This is the true mechanism of light.