In the Physical Sea model, "Dark Energy" is the Internal Tension () or elastic potential energy of the Sea medium itself. As the medium thins, it releases stored energy, which manifests as an outward-pushing expansion pressure.
The internal tension of the Sea is a function of its current density .
As the density decreases, the "stress" in the medium's lattice is relieved, pushing the boundaries of the universe outward.
Unlike "vacuum energy," which is constant, the expansion pressure of the Sea depends on the rate of its own thinning ().
Acceleration occurs when the thinning rate reaches a critical threshold where the release of elastic potential energy outweighs the "self-gravity" of the medium's density.