1) Maxwell derived equations showing that changing electric fields induce magnetic fields and vice versa, allowing electromagnetic waves to propagate through space. 2) These electromagnetic waves travel at the speed of light and have oscillating electric and magnetic fields perpendicular to each other and the direction of propagation. 3) Plane electromagnetic waves satisfy the wave equation and can be described by sinusoidal functions with the electric and magnetic fields in phase but oriented at 90 degrees to each other.