Why is the speed of light or any other electromagnetic radiation in vacuum, a fixed value anywhere in the Universe?

Imagine that a photon is nothing but a break in the space (or rather space-time) which forms the Universe and that the three dimensional space we see is a perceptional notion.

What if 'C' is not absolute velocity but rather a 'relative' velocity? Could it be because our perception of the Universe is travelling in the opposite direction with velocity 'C'? What if the direction of motion of the photon irrelevant in such a warped space time. This warping or distortion of the space-time being caused by the gravitational effect of the massive bodies in the Universe.

That would make photons and all other electromagnetic radiations 'windows' to whatever is outside the Universe.