Do photons know the future?

Photons are particles with zero rest mass moving in a vacuum at the speed of light. As bosons, they are not constrained by the Pauli Exclusion Principle and can pass through each other or occupy the same quantum state. In addition, they exhibit particle-wave dualism, which means that sometimes the motion of a particle fits the description of their behaviour and at other times they behave more like a wave. Therefore, the term quantum of electromagnetic waves is also appropriate for them.

Photons move in a straight line in a homogeneous environment, but if they encounter an environment with different properties, their trajectory may change. When they hit a mirror, they bounce off it according to the principle that the angle of incidence equals the angle of reflection. This principle is relatively easy to figure out and was therefore known since ancient times.