Time's Unidirectional Flow Proven by Complex Light Solution

Scientists have discovered a new equation that explains the behavior of light passing through an interface, such as glass or water. The equation, derived in a universe with one space dimension and one time dimension, shows that the speed of light is not always constant and that time can only move forward. This suggests that the arrow of time, which is important in physics, might be an intrinsic property of nature that even light obeys. The equation also resolves the long-standing controversy regarding the momentum of light when it enters a medium, providing a solution that conserves momentum through relativistic effects.