What if galaxies were made of dark energy?

Have you ever wondered what would happen if galaxies were made of dark energy? A recent study has discovered universal relations for non-rotating fluid spheres composed of this mysterious substance. Scientists used the extended Chaplygin gas equation of state to integrate the relevant differential equations and find the unknown coefficients of the functions. They discovered that the form of these functions does not depend on the details of the underlying equation of state. In other words, regardless of how dark energy behaves, the relations between normalized moment of inertia, dimensionless deformability, and compactness factor remain the same. This is a significant step forward in our understanding of the universe and its most enigmatic components.

The study used the extended Chaplygin gas equation of state, which is a generalization of the Chaplygin gas equation of state. This equation was proposed to describe the behavior of dark energy and has the form P = -A/ρ, where P is the pressure, ρ is the density, and A is a constant. The extended equation of state includes an additional term that accounts for radiation pressure. Scientists integrated the Tolman-Oppenheimer-Volkoff (TOV) equations to obtain the universal relations. The TOV equations describe the hydrostatic equilibrium of a neutron star or another compact star. The universal relations obtained in the study are independent of the details of the underlying equation of state, meaning they are valid for any type of dark energy that obeys the extended Chaplygin gas equation of state.