Answer:
Physics, Quantum Mechanics
Step-by-step explanation:
Light is a stream of photons with no weight. If you want to dig deeper in this mysterious phenomena, you should study physics and quantum mechanics. Physics takes up things like the theory of relativity, which can be useful in studying spacetime and how light travels through it, and quantum mechanics, being the study of matter in an atomic level, should help you get an understanding on how photons of light travel and why they behave so strangely.