Three-dimensional space displacement through a fourth spatial dimension explains both light speed value and special relativity

The special theory of relativity (STR) is based on two apparently contradictory postulates: The equality of all physical laws in all inertial reference systems and the invariance of the speed of light ( c ). This results in counterintuitive conclusions, including time dilation, object length contraction (i.e., Lorentz contraction), and mass increase at relativistic speeds as well as the unification of mass and energy. Although the STR has been empirically confirmed, the ultimate cause of special relativity as well as the reason for the invariance of c and its actual value (2.99 × 10 8 m/s) remain unknown. We have recently postulated that a hypothetical displacement of the three-dimensional (3D) space where we live throughout a fourth spatial dimension, which would be the basis for time, is a requirement for the gravitational effects contemplated by the general theory of relativity. This tetra-dimensional model of the universe explains that the actual value of c equals the speed at which our 3D space displaces along the fourth dimension. It also explains time dilation, Lorentz contraction, Lorentz transformation, and mass increase at relativistic speeds, as well as the unification of mass and energy, as epiphenomena derived from the projection of the fourth dimension to our 3D space. We conclude that our universe model can intuitively explain special relativity as well as the reason for the invariance of c and its actual value.