2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124228New corrections to the equation of motion and total collapsing time of an empty spherical cavity immersed in an infinite incompressible medium are proposed on the assumption of a non-uniform density. The dimensionless number quantifying the corrections with respect to the standard Rayleigh results (coined the $Δ$-factor) is fully independent of other possible contributions like surface tension and viscous terms. The $Δ$-factor effect advocated here can be seen as a direct consequence of a mass-shell non-trivial solution to the continuity equation. The consistency of the corrections with respect to the Bernoulli theorem and some physical consequences in the framework of the Rayleigh-Plesset equation are also discussed.12 pages, no figuresFluid Dynamicstext