The FLRW perturbation, modeling a granular universe, geometrically generates the observed cosmological constant

Several models have been proposed to explain the cosmological constant because of alterations in the distance-redshift relation caused by the universe’s inhomogeneities. We modelled the universe as a spherical galactic mass with a Gaussian radial profile, repeated at the nodes of a periodic 3D-lattice. The Einstein field density equation was solved to the second-order for the scalar field perturbation of the FLRW metric in the Newtonian gauge. The resulting metric solution is free of singularities. The diagonal Einstein spatial field equations exhibit only the subtraction of a second-order term. This term corresponds to a time-dependent cosmological constant in the reference frame comoving with the galaxy positions. This geometrically derived cosmological constant accurately predicts the current observed value using a realistic standard galaxy density profile, without introducing any additional adjustable parameters. This approach opens a track of research to explain the origin of the cosmological constant and of the Hubble tension within the framework of pure general relativity.