Science does not assume that light is magnetic without proof. The understanding that light has an electromagnetic nature is not merely an assumption but is supported by extensive experimental evidence and the well-established framework of electromagnetism.
The concept that light is an electromagnetic wave was first proposed by James Clerk Maxwell in the 19th century. Maxwell's equations mathematically described the behavior of electric and magnetic fields and predicted the existence of electromagnetic waves, including light. These equations successfully explained various phenomena related to electricity, magnetism, and optics.
Subsequent experimental investigations, such as those conducted by Heinrich Hertz, confirmed the existence of electromagnetic waves, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. These experiments demonstrated that electromagnetic waves propagate through space with properties similar to those predicted by Maxwell's equations.
The interaction of light with electric and magnetic fields was further established through numerous experiments and observations. For example, the phenomenon of light polarization, where the orientation of the electromagnetic wave's electric field oscillates in a specific direction, can be explained by the interaction between light and electric fields.
Additionally, the understanding of light as an electromagnetic wave is consistent with the principles of quantum mechanics. Quantum electrodynamics, which combines quantum mechanics and electromagnetism, successfully explains various phenomena related to the behavior of light and its interaction with matter.
In summary, the idea that light is an electromagnetic wave is not a baseless assumption but a well-supported scientific understanding. It is derived from a combination of rigorous experimental observations, mathematical models, and theoretical frameworks that have been extensively tested and validated over time.