[Mr. Nobody]

Relativity indicating that space itself has physical properties. If space has physical properties, then space is a physical entity medium and thus light is the vibrations of that substance and not a particle of light or photon.

Though spacetime is a visualization of Relativistic interactions; it is only a mathematical description of the relationship of moving objects as an observer would perceive them either visually or by measurement. Relativity does not define the absolute position of objects at the instance of observation, it only defines how an observer would see or measure the position of the object or its interactions. As a consequence of Relativity, the character and interactions of space itself is also described by General Relativity. Special Relativity only defines the spacetime-continuum geometry without the consideration of the effects of mass.

Relativity uses spacetime as the mathematical model to illustrate relative interaction issues, that is exactly my point. So, how does it indicate that space has physical properties? You yourself just reduced it to a mathematical model?