Historically, scientists have used the concept of a medium to explain phenomena that could not be directly observed, such as electricity and magnetism. However, after the Michelson-Morley experiment failed to detect a medium using the speed of light, and the special theory of relativity successfully explained this behavior without requiring a medium, the idea gradually fell out of favor among physicists. Another significant challenge to reintroducing a medium is that the special theory of relativity has been validated across all scales, making it difficult to justify the existence of such a medium within current physical theories.

Let’s explore how the properties of Aakasha are specifically designed to address the challenges associated with introducing a medium in physics, such as reconciling with the results of the Michelson-Morley experiment and the validation of the special theory of relativity at all scales.

The central principle of special relativity is that the space-time metric remains flat for all inertial frames. To model this, we propose that space-time, represented as Aakasha, is orthotropic - much like the structure of wood. In this framework, space is assumed to be isotropic and possesses significantly higher stiffness compared to the stiffness along the time axis. Consequently, a particle at rest within the spatial dimensions of Aakasha does not induce any stress. However, when a particle moves, it generates shear stress by rotating into the time axis, which we refer to as the inertia axis. This mechanism will be similar to how the base-isolated structure shown in the picture below filters ground motion being transferred to the structure. For a particle at rest, the time axis remains unrotated. For other inertial frames, since the shear stress does not cause curvature in the space-time fabric, the metric remains flat across all inertial frames.

 The energy associated with rest mass arises from the assumption that all particles are moving along the time axis at the speed of light. Time, in this context, is defined as the intervals between events measured along the inertia axis by each observer, with positive time corresponding to the direction of expansion of the universe.

A base-isolated structure that filters the earthquake motion.

Next, we examine how the space-time metric - flat in inertial frames - becomes curved in the presence of gravitational objects. Leveraging the properties of Aakasha, we define that any strain in the spatial dimensions of space-time induces an equivalent, opposite strain along the time axis. In engineering mechanics terms, this means the Poisson’s ratio between space and time is one, while between spatial directions it is zero. As a result, space in Aakasha behaves as an incompressible medium. In the particle model discussed earlier, the bare mass displaces Aakasha and causes compressive strains within the inclusion in space, as well as an equivalent expansion along the inertia axis. The resulting stresses and strains in both the inclusion and the matrix can be determined by applying engineering mechanics principles, and these are responsible for the curvature observed near a particle.

When a massive star undergoes gravitational collapse, its final state - whether a neutron star or a black hole - is determined by its initial size and the differential stress at the scale of a particle or fermion. In this model, if the differential stress is sufficient to strip the bare mass from the inclusion, a black hole forms; otherwise, the collapse results in a neutron star. Furthermore, the bare mass stripped from the inclusion is proposed as a candidate for dark matter. This perspective implies that the gravitational metric is only applicable outside the central core, thereby eliminating the singularity predicted by classical general relativity. Additionally, frame-dragging effects, such as those described by Einstein and the Lens-Thirring effect, can be attributed to physical models rather than mathematical artifacts.